4x5 processing

[tom_4558]

I'm new to 4x5 processing and I have been having a difficult time with my processing. I'm using D76 kodak stop bath and kodak fixer. I used these recently while processing Agfa APX 100 film. My results were 2 neg's ok and the others were thin showing hardly any detail at all. I use a Yankee daylight tank and process 6 sheets at a time. Process time 12 minutes in 68 degree solution. Could someone give me some pointers as to what may be the problem and what literature would be of great use to a novice such as myself? Any help is greatly appreciated. Thanks again. Tom

[Peter Collins]

This sounds like a fairly straightforward problem to solve. From the information you give regarding time and temperature of development, plus the fact that 2 negs were okay, it seems like there are two places to look.

I speak from personal failure, er, ah, experience.

First, especially since some work seems okay, is that you made a simple metering and/or placement error. That is, you didn't get the luminance of the important shadow areas measured correctly, or if you did, you didn't place it correctly. By "place it correctly" I mean, (1) if you are thinking along the lines of the Zone System, that you thought of the shadow area as Zone I or II, too dark for holding shadow detail, or (2) that, if using filters, you didn't adjust the indicated exposure by the amount needed for the specific filter (this can make 1 - 3 stops difference), or (3) you just set the shutter/aperture wrong. I have made all these mistakes as recently as May and June of this year....

Second, you may wish to reduce the effective speed of the film. For example, many users expose 100TMX (new TMax) at EI 64 instead of the manufacturer's rating of 100. For many users, this exposure is determined from testing to find the time necessary to expose for film-base-plus-fog to achieve a threshold negative density. Testing is important, but not essential--you may find what works for you by trial and error. You want to get important shadow detail on the straight-line portion of the film's characteristic curve. More information, with directions on how to do the testing, still current after 20+ years, is found in Ansel Adam's The Negative.

[ronald moravec]

If I understand, out of a run of six negs, two were ok and four thin. This sounds like four were underexposed.

Check your shutter speeds. Repeat using the same speed and varying the stop.

Are you loading the holder with the film ID notches in the upper right corner so you are sure the emulsion is up?

Try processing one sheet in a 8x10 tray,emulsion up. Use 16 oz of developer and lifting each side of the tray every 15 sec. This means you will work your way around in 60 sec an start again. Fix may be done in a 5x7 tray. Let the film slop around in the developer as much as possible to eliminate agitation patterns. You will get very even development , but be limited to one sheet at a time.

Don`t allow the timer to fog the film. Set up a baffle and/or cover the tray with waterproof something.

With as much information as we have, all I can say is check each step along the way.

[paulr]

i have to agree with Peter and Ronald. something to look at on the thin negs: are the shadow areas particularly thin or missing, or is there information in the shadows, but very little density in the highlights? i'm guessing the answer will be the first one, which would indicate underexposure.

i used to use apx100 4x5, developed in d76 (1:1) and found that the true speed of the film was about 50. that one stop of added exposure, plus some more careful metering of the highlights, might solve your problem.